Products

Bitumen emulsion plants in general

A bitumen emulsion plant can be either a batch type or continuous and in most cases incorporates a colloid mill. In the manufacturing process, an emulsifier solution (‘soap’) and hot bitumen are passed through the colloid mill, where the emulsification takes place. The soap solution contains water, emulsifier, acid or base and if required a stabilizer such as calcium chloride, which are carefully mixed in such proportions that a uniform solution with the right pH-value is obtained. A solvent such as naphtha, mineral spirits, kerosene or diesel oil, is often also part of the emulsion. It can be mixed in with the bitumen, the emulsifier solution or the emulsion after the colloid mill. Polymers in latex form such as natural rubber or SBR may be incorporated preferably in the soap phase or to the emulsion after production. Polymers such as SBS or EVA are pre-dispersed in the bitumen phase.

Before production starts, a formulation is optimised in the laboratory to give a suitable emulsion with regard to performance in the application and specification.

Batch Plants

In a batch plant, the emulsifier solution (soap) is prepared and brought to temperature in a batch tank. If solvent is to be used and if it is to be added to the bitumen, then a batch tank is needed for the bitumen as well, or the solvent will have to be dosed in-line. The bitumen and water can be measured by using a level gauge on the tank. The small volume materials, i.e. solvent and the chemicals should be weighed or metered in by a more sensitive device.

Batch Plant

In the simplest batch plants the bitumen and soap batches are prepared in the volumes corresponding to the desired bitumen residual and then gravity-fed through the colloid mill until the batch tanks are empty. A much better set-up includes dosage pumps making it possible to keep the desired residual through the whole production, giving a better end-quality.

In-line Plant

In-line Plants

The in-line plant has no batch tanks; bitumen and emulsifier solution come directly from the supply. The soap is prepared automatically and in accordance with the selected formulation by injecting emulsifier, acid and stabilizer into the water line, where the reaction between the emulsifier and the acid takes place before the water enters the mill. The water is heated to suitable temperature by a continuous heater. Heat can be recovered from the emulsion cooler. The continuous plant requires emulsifiers that easily disperse in water in order to allow fast reaction with acid or alkali. A pH-probe, attached to the water line just before the mill, controls the dosage of the acid or alkali.

The bitumen and (if required) solvent are also continuously fed to the mill. The bitumen is kept in a tank at correct temperature. The continuous plant can run as long as there are material and storage space available.

The main advantages of continuous plants over batch plants are:

  Quick change from one emulsion type to another

  Less labour and lower handling costs are required

  Health hazards related to the handling of chemicals are almost eliminated

  Higher utilization by elimination of the time required to prepare for batches

  Heat can be recovered simply from the emulsion via a cooler and used to heat
    the incoming water. In a batch plant this heated water needs to be stored
    until the next soap production.

Denimo Tech Emulsion Plants

Denimo Tech offers a range of emulsion plants, both batch and in-line design, suitable for all emulsion producers. Features of the plant include the very highest quality materials including corrosion-resistant alloys, closed systems for safe handling of chemicals (even for batch plants), and a range of optional instrumentation and automation packages from simple manual controls and flow control based on temperatures to sophisticated remote production control systems.

If you desire an emulsion plant please download the questionnaire from the download section of this homepage. Fill in as much information in the blanks as you are able to, in order for Denimo Tech to supply you with quotation on suitable equipment.